Human drug delivery device for tinnitus

ABSTRACT

A neural prosthetic drug delivery apparatus for reducing or eliminating the effects of tinnitus. The apparatus includes a catheter which is inserted into the patient&#39;s auditory cortex or thalamus. The catheter microinfuses drugs which suppress or eliminate abnormal neural activity into geometrically separate locations of the patient&#39;s brain, thereby reducing or eliminating the effects of tinnitus. In one embodiment the apparatus includes a stimulation device for outputting processed electrical signals and an electrode having a plurality of electrical contacts which is arranged in a target zone of the patient&#39;s brain. Each of the plurality of electrical contacts independently outputs electrical discharges in accordance with the electrical signals.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. patent application Ser.08/332,755, filed Nov. 1, 1994, pending, which is a continuation-in-partof U.S. patent application Ser. No. 08/194,017, filed Feb. 9, 1994,which issued as U.S. Pat. No. 5,496,369 on Mar. 5, 1996, the contents ofeach of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to an apparatus for treating tinnitus,and in particular, to a prosthetic drug delivery device formicroinfusing portions of drugs at geometrically separate locations ofthe patient's primary auditory cortex or the patient's thalamus.

2. Background of the Related Art

Tinnitus is a disorder where a patient experiences a sound sensationwithin the head ("a ringing in the ears") in the absence of an externalstimulus. This uncontrollable ringing can be extremely uncomfortable andoften results in severe disability. Tinnitus is a very common disorderaffecting an estimated. 15% of the U.S. population according to theNational Institutes for Health, 1989 National Strategic Research Plan.Hence, approximately 9 million Americans have clinically significanttinnitus with 2 million of those being severely disabled by thedisorder.

There are no treatments currently available that consistently eliminatetinnitus although many different types of treatments have beenattempted. This wide variety of attempted treatments attests to theunsatisfactory state of current tinnitus therapy. Several more commonattempts will be discussed below.

One approach involves suppression of abnormal neural activity within theauditory nervous system with various anticonvulsant or local anestheticmedications. Examples of such anticonvulsant medications includexylocaine and lidocaine which are administered intravenously. Inaddition, since the clinical impact of tinnitus is significantlyinfluenced by the patient's psychological state, antidepressants,sedatives, biofeedback and counseling methods are also used. None ofthese methods has been shown to be consistently effective.

Another widely used approach to treating tinnitus involves "masking"undesirable sound perception by presenting alternative sounds to thepatient using an external sound generator. In particular, an externalsound generator is attached to the patient's ear (similar to a hearingaid) and the generator outputs sounds into the patient's ear. Althoughthis approach has met with moderate success, it has several significantdrawbacks. First, such an approach requires that the patient not be deafin the ear which uses the external sound generator. That is, theexternal sound generator cannot effectively mask sounds to a deaf earwhich subsequently developed tinnitus. Second, the external soundgenerator can be inconvenient to use and can actually result in loss ofhearing acuity in healthy ears.

Yet another approach involves surgical resection of the auditory nerveitself. This more dangerous approach is usually only attempted if thepatient suffers form large acoustic neuromas and tinnitus. In thissituation, the auditory nerve is not resected for the specific purposeof eliminating tinnitus but is removed as an almost inevitablecomplication of large tumor removal. In a wide series of patients withtinnitus who underwent this surgical procedure of acoustic nerveresection, only 40% were improved, 10% were improved and 50% wereactually worse.

An alternative and somewhat more successful approach involves electricalstimulation of the cochlea. In patients who have tinnitus and havereceived a cochlear implant, as many as half reported some improvementin their tinnitus after implantation. Round window stimulation has alsobeen useful in improving tinnitus in selected patients. However, thesuccess rate of this approach has also remained relatively low.

Prior to the nineteenth century, physicians and scientists believed thebrain was an organ with functional properties distributed equallythrough its mass. Localization of specific functions within subregionsof the brain was first demonstrated in the 1800s, and provided thefundamental conceptual framework for all of modern neuroscience andneurosurgery. As it became clear that brain subregions served specificfunctions such as movement of the extremities, and touch sensation, itwas also noted that direct electrical stimulation of the surface ofthese brain regions could cause partial reproduction of these functions.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide a therapeuticapparatus which can be placed in one of a patient's cerebral cortex orin the patient's thalamus to reduce the effects of tinnitus.

Another object of the invention is to provide a therapeutic apparatuswhich can be positioned in the brain such that electric discharges canbe accurately delivered to geometrically dispersed locations in eitherthe cortex or thalamus.

Another object of the invention is to provide a therapeutic device whichallows a physician to physiologically test location and function of atleast one to reduce or eliminate the patient's tinnitus.

Another object of the invention is to provide a therapeutic apparatuswhich can be positioned in the brain such that microinfusions of a drugthat reduces abnormal neural activity, the latter leading to symptoms oftinnitus, such that the drug can be administered in geometricallydispersed locations in the patient's cortex or thalamus.

Another object of the invention is to provide a therapeutic deviceapparatus which can support a reservoir of the drug so that themicroinfusions can be continuously administered.

One advantage of the invention is that it reduces or eliminates theeffects of tinnitus.

Another advantage of the invention is that it can utilize a singleelectrode.

Another advantage of the invention is that it can utilize a singlecatheter.

Another advantage of the invention is that it penetrates the brain asopposed to resting on the brain surface, thus requiring significantlyless current to stimulate localized areas of the cortex or the thalamus.

Another advantage of the invention is that it penetrates the brain thusrequiring significantly lower doses of the drug and hence reducesunwanted side effects related to inadvertent treatment of surroundingtissue.

Another advantage of the invention is that the contacts are sufficientlyclosely arranged next to each other to provide high geometric resolutionstimulation of the auditory cortex.

One feature of the invention is that it includes a penetratinglongitudinal support or electrode.

Another feature of the invention is that it includes multiple contactson the longitudinal support.

Another feature of the invention is that it includes a stimulationdevice.

Another feature of the invention is that each contact can separatelyintroduce electrical discharges in the primary auditory cortex.

Another feature of the invention is that it utilizes a catheter toadminister micro-infusions of the drugs to geometrically separatelocations in the patient's cortex or thalamus.

Another feature of the invention is that the catheter includes anelectrode for recording discharges in the patient's cortex or thalamus.

Another feature of the invention is that it utilizes a drug reservoirfor containing reserve portions of the drug.

Another feature of the invention is that it can include a flexible wiremulticontact electrode.

Another feature of the invention is that the flexible wire multicontactelectrode is inserted into the brain using a rigid introducer.

Another feature of the invention is that a flat plastic plate attachedto the longitudinal support (electrode) at the site of skull attachmenthelps position the prosthetic in the auditory cortex. The flat plasticplate having a cup to receive a sphere coupled to leads whichinterconnect the a speech processor.

These and other objects, advantages and features of the presentinvention will become more apparent from the following description ofembodiments thereof taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B show the orientation of a patient's primary auditorycortex in relation to the patient's cochlea and cochlear nucleus.

FIG. 2A shows a multi-contact recording/stimulating electrode system 100for blocking and/or masking the abnormal electrical activity present intinnitus patients according to one embodiment of the invention. FIG. 2Bshows a human cerebral cortex neural therapeutic device according to oneembodiment of the invention.

FIG. 3A shows a side view of a plane A which intersects a coronalsection with a Sylvian fissure exposed, and FIGS. 3B and 3C show thecoronal section before and after tissue is digitally "peeled off" theSylvian fissure.

FIG. 4 shows a neural therapeutic device with a support havingelectrical contacts and its stimulation device.

FIG. 5 shows a therapeutic device which includes two longitudinalsupports according to another embodiment of the invention.

FIG. 6 shows a therapeutic device according to yet another embodiment ofthe invention.

FIG. 7A shows the prosthetic of FIG. 6 as looking down on the patient'sbrain surface, FIG. 7B shows a closer view of a stopping piece with acup and a lid, and FIG. 7C corresponds to FIG. 7A with the supportinserted.

FIG. 8 shows another embodiment of the invention involving drug-infusioninto regionally targeted locations within the brain according to anotherembodiment of the invention.

FIG. 9 shows a closer view of a catheter with ports or openings.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

It is presumed that patients perceive tinnitus because neurons withinthe central auditory system (Auditory Cortex and/or Medial GeniculateNucleus (MGN) of the Thalamus) are firing abnormally. By usingsophisticated medical imaging and neurosurgical techniques discussed inU.S. patent application Ser. No. 08/194,017, now U.S. Pat. No. 5,496,369the contents of which are incorporated herein by reference, specificregions in the brain can be targeted and the abnormal electricalactivity blocked or masked with stimulating electrodes or with drugsdelivered through precisely placed brain catheters.

The primary auditory region of the human brain is buried deep within theSylvian fissure. It is not visible from the brain surface and its exactlocation varies slightly from one person to the next.

The minimal stimulation threshold for eliciting sound sensations wasfound to be 6 milliamperes, which is too high to be toleratedchronically and is thousands of times greater than currents foundsubsequently to be required to generate phosphenes in visual cortexusing penetrating electrodes.

Recent advances in MRI and computer technology now allow detailedpreoperative imaging of human auditory cortex.

An important aspect of the cochlear implant technology, which is nowhighly refined, involves transducing sound into complex electricalstimulation sequences. This large body of technical knowledge developedover the last twenty years will be directly applicable to the treatmentof tinnitus via the auditory cortex therapeutic device.

Normal Hearing

Mechanisms of human hearing are reviewed briefly to provide a frameworkfor discussion of the tinnitus masking system. The auditory system iscomposed of many structural components that are connected extensively bybundles of nerve fibers. The system's overall function is to enablehumans to extract usable information from sounds in the environment. Bytransducing acoustic signals into electrical signals that can then beprocessed in the brain, humans are able to discriminate amongst a widerange of sounds with great precision.

FIGS. 1A and 1B show a side and front view of areas involved in thehearing process. In particular, the normal transduction of sound wavesinto electrical signals occurs in cochlea 110, a part of the inner earlocated within temporal bone (not shown). Cochlea 110 is tonotopicallyorganized, meaning different parts of cochlea 110 respond optimally todifferent tones; one end of cochlea 110 responds best to high frequencytones, while the other end responds best to low frequency tones. Cochlea110 converts the tones to electrical signals which are then received bycochlear nucleus 116. This converted information is passed from cochlea110 into brain stem 114 by way of electrical signals carried along theacoustic nerve and in particular, cranial nerve VIII (not shown).

The next important auditory structure encountered is cochlear nucleus116 in brain stem 114. As the acoustic nerve leaves the temporal boneand enters skull cavity 122, it penetrates brain stem 114 and relayscoded signals to cochlear nucleus 116, which is also tonotopicallyorganized. Through many fiber-tract interconnections and relays (notshown), sound signals are analyzed at sites throughout brain stem 114and thalamus 126. The final signal analysis site is auditory cortex 150situated in temporal lobe 156.

The mechanisms of function of these various structures has also beenextensively studied. The function of cochlea 110 is the mostwell-understood and the function of auditory cortex 150 is the leastunderstood. For example, removal of the cochlea 110 results in completedeafness in ear 160, whereas removal of auditory cortex 150 from oneside produces minimal deficits. Despite extensive neural connectionswith other components of the auditory system, auditory cortex 150 doesnot appear to be necessary for many auditory functions.

Advanced imaging combined with an intraoperative stereotactic system nowenable placement of penetrating electrodes into auditory cortex duringroutine epilepsy surgery without dissection of the Sylvian fissure.

Primary auditory cortex 150 in FIGS. 1A and 1B is tonotopicallyorganized, meaning stimulation in different areas is likely to cause thepatient to perceive different tones. These tones form the buildingblocks of complex sound phenomena such as speech. Tonotopic organizationis a fundamental characteristic of the cochlea and cochlear nucleus aswell, as discussed above. Auditory cortex 150, however, has itstonotopic map stretched across a larger volume of tissue (greater thattwice the volume of cochlear nucleus 116). Greater tissue volume enablesplacement of a greater number of electrical contacts for a giventonotopic zone. This results in increased signal resolution and improvedclarity of auditory sensation. Finally, because of anatomicaldifferences, auditory cortex 150 can accommodate penetrating electrodearrays.

Stimulating Electrode

FIG. 2A shows a multi-contact recording/stimulating electrode system 100for blocking and/or masking the abnormal electrical activity present intinnitus patients according to one embodiment of the invention. Inparticular, system 100 includes a multi-contact stimulating/recordingelectrode 104 connected to cables 108 via connector 112. Cables 108enter skull 116 at burr hole opening 120 of skull 115 and are connectedto a stimulation device 410 positioned in subcutaneous tissue of axialskeleton (thorax or abdomen).

FIG. 2B shows a closer view of multi-contact stimulating/recordingelectrode 104 of electrode system 100. Electrode 104 has a first end206a and a second end 206b which is blunt or smoothly curved. Electrode104 has electrical contacts 220 along a longitudinal support 226.Support 226 can be anywhere from several millimeters long to severalcentimeters long. Electrical contacts 220 are small metal pads which canbe separately electrically charged via respective wires 232 available atfirst end 206a. Wires 232 are coupled to stimulation device 410 (seeFIGS. 2A and 4). Electrical contacts 220 are spaced approximately 10micrometers to several millimeters apart and preferably approximately 50to 150 micrometers apart. Each of electrical contacts 220 can separatelyintroduce electrical discharges in the primary auditory cortex inaccordance with electrical signals outputted from stimulation device410. Application of a voltage to contacts 220 near first end 206aresults in stimulating low (or high--to be determined by questioning thepatient) tones in auditory cortex 150 (see FIGS. 1A and 1B), whereasapplication of a voltage to contacts 220 near second end 206b results instimulation of high (or low) tones in auditory cortex 150.

Electrode 104 is stereotaxically placed into the primary auditory cortexof the patient with tinnitus. This can be done using a standardstereotaxic head frame under local anesthesia. That is, the abovediscussed three dimensional computerized MRI reconstruction method ofFIGS. 3A-3C is used to stereotaxically place electrode 104 within thetargeted region of auditory cortex 150. Correct placement is confirmedby presenting a series of tones to the patient and mapping the tonotopicresponses of the neurons along electrode 104.

In deaf patients, this mapping procedure is not possible, but mappingcan still be carried out using microstimulation currents delivered tovarious contacts along electrode 104. The deaf patient describes therelative pitch of the sounds he or she perceives following stimulation,whereby the electrically stimulated location and parameters which mostclosely match the patient's tinnitus are determined. This approach couldbe used in the thalamus (MGN) as well, but the preferred embodimentinvolves implantation in the cortex. Regardless of whether or notstimulating electrode 104 is placed into the correct region of thecortex or into the correct region of the MGN, electrode 104 is coupledto stimulation device 410 via cables 108 and in particular, wires 232a.

Longitudinal support 226 can be a rigid support or a flexible wire witha rigid introducer which enables the physician to introduce electrode104 into a patient's brain and then subsequently remove the rigidintroducer thereby exposing electrical contacts 220 to auditory cortex150. Support 226 can be one of the probes shown in FIGS. 3-5 in"Possible Multichannel Recording and Stimulating Electrode Arrays:.ACatalog of Available Designs" by the Center for Integrated Sensors andCircuits, University of Michigan Ann Arbor, Mich., the contents of whichare incorporated herein by reference. Alternative electrodes such asDepthalon Depth Electrodes and interconnection cables from PMTCorporation 1500 Park Road, Chanhassen, Minn., 55317 could also be usedas support 226 and electrical couplers between contacts 220 and a speechprocessor (410 in FIG. 4).

Electrical contacts 220 can operate as high impedance (megohms) contactsor low impedance (a few ohms to several thousand ohms) contacts. Thisenables the contacts to output a small (a few microamperes as opposed toa few milliamperes) current. High impedance contacts localize thepotentials applied to the patient's primary auditory cortex toapproximately a few hundred micrometers. The localization appliedelectric charges corresponds to the tonotopic spacing of nerve cellpairs.

Electrode 104 is arranged along a longitudinal direction of auditorycortex 150. However, auditory cortex 150 is located in the transversetemporal gyrus and is buried deep within the Sylvian fissure.Consequently, its location cannot be determined simply by looking at anexposed surface of the brain. Therefore, MRI imaging techniques must beemployed to reveal the exact orientation of auditory cortex 150.

A single coronal image of an individual's brain cannot reveal the exactorientation of auditory cortex 150. However, for treatment of tinnitus,a standard coronal MRI provides a fairly good estimate as to thelocation of the target region, whether or not the target region is theauditory cortex or the thalamus. However, if more precise targeting isdesired, a series of two dimensional images must be obtained and aresulting 3-D MRI image constructed. Once such an image is constructed,the digital data making up that image can be transformed to provide aview of the Sylvian fissure. This in turn exposes auditory cortex 150 asa mole-like mound. That is, tissue on top of the digital image can be"peeled off" to expose the sylvian fissure and consequently auditorycortex 150 "pops out" of the image. This process is described in"Three-dimensional In Vivo Mapping of Brain Lesions in Humans", by HannaDamasio, MD, Randall Frank, the contents of which are incorporatedherein by reference.

FIG. 3A shows a side view of a plane A which intersects a coronalsection 310 as well as a view of coronal section 310 with Sylvianfissure 316 exposed. FIGS. 3B and 3C show coronal section 310 before andafter tissue is digitally "peeled off" to expose auditory cortex 150.One or more resulting mounds 320 is revealed in FIG. 3C and this moundcorresponds to auditory cortex 150 of FIG. 1B. Mound 320 does not appearuntil after tissue on the underside of Sylvian fissure 316 isreconstructed to provide the 3-D image. Once the exact location andorientation of mound 320 and consequently auditory cortex 150 have beendetermined using these 3-D MRI image processing techniques, electrode104 can be accurately inserted into auditory cortex 150.

FIG. 4 shows electrode 104 just prior to insertion into auditory cortex150. In addition, FIG. 4 shows stimulation device 410 coupled to wires232 via cable 108. Stimulation device 410 is a chronic electricalstimulation device. This stimulator device is well tested and widelyavailable. Examples include chronic epidural stimulators made byMedtronics used for chronic back and leg pain and deep brainstimulators, as well as nearly all types of cochlear implants.

The above electrical implantation technique for tinnitus is quick andsafe, e.g., over 100 auditory cortex region electrode implantations havebeen performed in patients being evaluated for medically intractableseizures as reported by a French epilepsy surgery group. In addition,since electrode 104 is placed in the exact site of presumed abnormalneuronal electrical activity, it is much more effective in disrupting oraltering abnormal neuronal electrical activity, thereby eliminatingtinnitus. Moreover, preliminary testing has shown that placement ofelectrode 104 within the central auditory system causes patients toperceive sounds, and this will likely be the case even in patients whoare deaf from causes refractory to cochlear implantation. Also,stimulation in the auditory cortex does not impair hearing in tinnituspatients who do have good hearing.

FIG. 5 shows an electrode 510 which includes two longitudinal supports226a and 226b according to another embodiment of the invention. Althoughtwo supports are shown, three or more such supports could be used.Longitudinal support 226a is connected to cable 108a containing wires232a via connector 112a and longitudinal support 226b is connected tocable 108b containing wires 232b via connector 112b. Cables 108a and108b are again connected to stimulation device 410 as in FIG. 4.

FIG. 6 shows an electrode 610 according to yet another embodiment of theinvention. In particular, FIG. 6 shows longitudinal support 226 withfirst end 606a and second end 606b. End 606a is arranged in the regionof auditory cortex 150 with low tones (or high tones as previouslydiscussed) and second end 606b is arranged in the region of auditorycortex 150 with high (or low) tones in a manner similar to first end206a and second end 206b of FIG. 2B. Here, however, longitudinal support226 has a sphere 616 which is stopped by a stopping piece 614. Thisenable the physician to insert longitudinal support 226 at a wide rangeof angles and yet secure electrode 610 once longitudinal support 226 hasbeen inserted.

FIG. 7A shows electrode 610 of FIG. 6 as looking down on the patient'sbrain surface 704. FIG. 7B shows a closer view of stopping piece 614with a cup 708 and a lid 714 with a notch 716 for passing leads 232.FIG. 7C corresponds to FIG. 7A with support 236 inserted into surface704 and sphere 616 resting in cup 708. FIG. 7C also shows lid 716covering sphere 616 with leads 232 extending out of notch 716.

FIG. 8 shows another embodiment of the invention involving drug-infusioninto regionally targeted locations within the brain. The alternativedrug-infusion treatment strategy relies on the same principal ofregionally targeted treatment within the brain, but employs a differenteffector to eliminate the abnormal neural activity causing tinnitus.Namely, a small drug infusion catheter 801 is stereotaxically placedinto either the auditory cortex or thalamus (MGN) and microinfusions ofvarious drugs that block abnormal neural activity are infused into thetargeted locations.

Referring in more detail to FIG. 8, a drug infusion catheter-recordingdevice 800 is connected to an injectable (rechargeable) drugreservoir-pump 804 via connector 803 which is secured with sutureswidely used in neurosurgery. Pump 804 is secured to the patient's skull808 under the scalp and is not exposed to the external environment. Pump804 has a valve 824 which can be accessed externally so that additionaldrugs can be injected via a syringe (not shown) without reopening thepatient's scalp. Catheter 801 has multiple-ports 814 from which thedrugs are microinfused into the targeted brain regions.

FIG. 9 shows a closer view of catheter 801 with ports or openings 814are arranged at discrete locations along catheter 801. Catheter 801 canbe made, for example, of silastic such as the catheters sold byRadionics, Codman, and Medtronics. Catheter 801 may be elongate and atleast substantially cylindrical as depicted in FIG. 9 but need not havea circular cross-section 817 and instead can be flat, elliptical or anyother shape which facilitates broader diffusion of the drug. Catheter801 can include a small embedded recording-stimulating electrode 819which can be connected to stimulation device 410 so that catheter 801can be properly positioned. Electrophysiologic recording data (recordedon a recording device) from this special catheter electrode will providephysiologic confirmation of proper catheter position in auditory cortex.The diameters of ports (or openings) 814 can be approximately between 10micrometers and several millimeters and preferably between approximately40 micrometers and 1 millimeter. The centers of ports 814 can also betens of micrometers apart to millimeters apart and the spacing need notbe uniform.

Pumps manufactured by Medtronics and Alzet can serve as injectable drugreservoir-pump 804. Examples of drugs that could be infused includeanticonvulsants such as dilantin, inhibitory neurotransmitters such asγ-aminobutyric acid (GABA) and local anesthetics such as lidocaine. Inhigh enough concentrations, these compounds should block abnormalneuronal discharges. By delivering the drugs to the specific centralnervous system target, significantly higher concentrations of the drugreach their target without exposing non-targeted surrounding tissue, ascompared to the concentrations which could be delivered by simplyadministering the same drug systemically, e.g. orally or intravenously.Consequently, this strategy should result in marked improvement inefficacy while avoiding toxic side effects.

The precise amount of drug infusion depends on the type of drug but canbe determined at the outset of implantation. In particular, catheter 801is initially inserted into the targeted location in the manner describedabove for insertion of electrode 104. The patient is then asked if thereis any noticeable reduction in ringing due to the tinnitus as the amountof drug infusion is manually adjusted. The amount of infusion is thatamount which is required to eliminate the ringing. Once the amount isdetermined, the appropriate chronic diffusion pump 804 is connected tocatheter 801 and all incisions are closed. Post-operative modificationsof infusion rates can be carried out using percutaneous radio controltechniques, e.g., Medtronics.

As mentioned above, the alternative drug-infusion treatment strategyrelies on the same electrode placement principals as described abovewith respect to FIGS. 3A-3C. Namely, a series of images must again beobtained and a resulting 3-D MRI image constructed. Once the image isconstructed, the digital data making up that image can be transformed toprovide a view of the Sylvian fissure. This in turn exposes auditorycortex 150 as a mole-like mound. Again, tissue on top of the digitalimage can be "peeled off" to expose the Sylvian fissure and consequentlyauditory cortex 150 "pops out" of the image.

Numerous additional modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeunderstood that the invention may be practiced otherwise than asspecifically claimed.

What is claimed is:
 1. A neural therapeutic apparatus for treatment of apatient with tinnitus, comprising:a drug reservoir-pump for containingand pumping a drug, wherein said drug is capable of reducing abnormalneural activity associated with tinnitus; and a drug delivering catheterfor arrangement in the patient's auditory, cortex or thalamus, said drugdelivering catheter operatively connected to said drug reservoir-pump,and said drug delivering catheter having a plurality of ports, each ofsaid plurality of ports capable of outputting said drug to predeterminedgeometric locations within said one of the patient's auditory, cortexand thalamus.
 2. The neural therapeutic apparatus as claimed in claim 1,further comprising:a stimulation device for outputting electricalsignals; and a stimulating and recording electrode arranged in said drugdelivering catheter, said electrode having a plurality of electricalcontacts electrically coupled to said stimulation device, and each ofsaid plurality of electrical contacts outputting one or more electricaldischarges in accordance with said electrical signals, wherein each ofsaid electrical contacts is capable of receiving electrical dischargesin said one of the patient's auditory, cortex and thalamus, and whereinsaid electrical discharge output blocks abnormal neural activity andalleviates the symptoms of tinnitus.
 3. The neural therapeutic apparatusas claimed in claim 1, wherein said drug capable of reducing abnormalneural activity comprises a neurotransmitter inhibitor.
 4. The neuraltherapeutic apparatus as claimed in claim 1, wherein said drug capableof reducing abnormal neural activity comprises an anticonvulsant.
 5. Theneural therapeutic apparatus as claimed in claim 1, wherein said drugcapable of reducing abnormal neural activity comprises dilantin orγ-aminobutyric acid.
 6. The neural therapeutic apparatus of claim 1,wherein said drug delivering catheter comprises silastic material. 7.The neural therapeutic apparatus of claim 1, wherein said drugdelivering catheter has a cross-sectional shape which is substantiallycircular or substantially elliptical.
 8. The neural therapeuticapparatus of claim 1, wherein said plurality of ports are arranged atdiscrete locations on said drug delivering catheter.
 9. The neuraltherapeutic apparatus of claim 8, wherein each of said plurality ofports are substantially circular and are from about 10 micrometers toabout 2 millimeters in diameter, and wherein said plurality of ports arespaced from about 6 micrometers to about 2 millimeters apart.
 10. Theneural therapeutic apparatus of claim 9, wherein the centers of each ofsaid plurality of ports are separated by a distance in the range of fromabout 20 micrometers to about 2 millimeters.
 11. A neural therapeuticapparatus for implantation in a target zone of a patient's brain,comprising:a reservoir-pump for containing a drug, said drug capable ofreducing abnormal neural activity, associated with tinnitus; a catheterfor delivering said drug to the target zone of the patient's brain, saidcatheter operably connected to said reservoir-pump, and comprising oneor more stimulating and recording electrodes; a stimulation device foroutputting electrical signals to said one or more electrodes, saidelectrodes outputting electrical discharges in accordance with saidelectrical signals, wherein said outputted electrical discharges blockabnormal neural activity; and a recording device operably connected tosaid one or more electrodes, said recording device capable of recordingelectrophysiologic data received by said one or more electrodes, fromsaid target zone of the patient's brain.
 12. The neural therapeuticapparatus of claim 11, wherein said catheter includes a plurality ofports, each of said plurality of ports capable of outputting said drugto a geometrically separate, predetermined location within said targetzone of the patient's brain.
 13. The neural therapeutic apparatus ofclaim 11, wherein said electrode has a plurality of electrical contacts,each of said plurality of electrical contacts electrically coupled tosaid stimulation device, with each of said plurality of electricalcontacts capable of outputting electrical discharges to said target zoneof the patient's brain, wherein each of said plurality, of electricalcontacts is further capable of receiving electrical discharges forrecording as electrophysiologic data from said target zone of thepatient's brain.
 14. The neural therapeutic apparatus of claim 11,wherein said reservoir-pump includes a recharging valve, and whereinsaid recharging valve is externally accessible.
 15. The neuraltherapeutic apparatus of claim 11, wherein said reservoir-pump isadapted for attachment to the patient's head, and wherein saidreservoir-pump is adjustable by a radio control means.
 16. The neuraltherapeutic apparatus of claim 11, wherein said drug is selected fromthe group consisting of an anticonvulsant, a neurotransmitter and alocal anesthetic.
 17. A neural therapeutic drug delivery apparatus forimplantation in a target zone of a patient's brain, comprising:means fordelivering a drug to said target zone of the patient's brain, said drugcapable of reducing abnormal neural activity associated with tinnitus;means for outputting electrical discharges to said target zone of thepatient's brain; and means for receiving electrical discharges from saidtarget zone of the patient's brain.
 18. The neural therapeutic drugdelivery, apparatus of claim 17, wherein said means for outputtingelectrical discharges and said means for receiving electrical dischargescomprise one or more stimulating and recording electrodes, and saidmeans for delivering said drug comprises a catheter comprising one ormore ports capable of outputting said drug to one or more predetermined,separate locations within said target zone of the patient's brain. 19.The neural therapeutic drug delivery apparatus of claim 18, wherein saidmeans for delivering said drug further comprises a radio-controlled pumpconnected to said catheter, and wherein said target zone is an auxiliarycortex or a medial geniculate nucleus of a thalamus.